Tearing or avulsion of soft tissue from bone is a relatively common type of injury, especially in sports, and can occur in many types of orthopedic injuries, such as torn or ruptured tendons and/or ligaments. In the shoulder, for example, portions of the rotator cuff tendons can tear within themselves or avulse from their insertion into the bone. FIGS. 1A-1B show superior views of a shoulder having a typically torn rotator cuff. Here, the tear is associated with the supraspinatus tendon as it inserts into the humerus. The subscapularis tendon and the coracoid process are also shown in FIG. 1A for reference.
The tear 10 shown in FIG. 1A is categorized as a simple tear because the tear branches normal to the muscle fibers, while the tear in FIG. 1B branches in both parallel and normal directions to the muscle fibers. In the case of both of these tears, such a torn rotator cuff can lead to pain, weakness, and loss of function.
In many cases, the rotator cuff is repaired by surgically reconnecting the edges of the torn muscle or tendon. Repairs may also include reconnecting the edges of any interstitial tear in the tendons, as well as approximating or reattaching the torn edge of the soft tissue to the bone where it originated. Common techniques for repairing tears to soft tissue and the avulsion of soft tissue from bone include using sutures through bone tunnels, suture anchors, friction anchors, tacks, screws with spiked washers and staples, or any combination of these techniques.
Any repair of a rotator cuff injury should have a secure fixation to soft tissue and should preserve the range of motion through which a muscle is expected to function after the repair. The fixation should also serve to provide a means for the soft tissue to anatomically reattach to a position in the shoulder, the humeral head in this case. In the shoulder, the soft tissues may experience wide ranges of motion, as shown by the views in FIGS. 2A-2B of a shoulder during internal and external rotations. In addition to these rotations, the shoulder may also be moved through adduction and abduction motions not shown. The various motions indicate that the soft tissue may undergo dramatic variations in stresses and that a wide variation in possible stresses at a particular point can occur. A surgical repair of injured soft tissue, such as the tears shown in FIGS. 1A-1B, preferably accounts for different requirements at various points along the injured site in order to alleviate concerns associated with the repair.
Failure of the repair is often instigated on the soft tissue site where, typically, suture is passed through the tendon in a number of ways. Failure occurs when the suture slices through the tendon while under tension. Common methods to alleviate this problem use multiple suture passes into the tendon using simple or mattress stitches. An alternative method uses complex stitches such as the massive cuff stitch.
FIG. 3A shows an example of the massive cuff stitch. A mattress stitch 131 is made horizontally in the tendon 20 and the suture tails are tied together, and a simple suture 130 is passed vertically medial to the mattress stitch 131 and is extended to a bone fixation point (not shown) by the suture tails 132. However, as seen in FIG. 3B, as the simple suture tails 136 receive a high enough load upon muscle contraction, the pass of the simple suture 130 tends to cut through the tendon 20 until it engages the tensile load of the mattress suture 133 at point 135. The distance that the suture 130 cuts though the tendon 20 can form a gap at the bone/tendon interface, which can inhibit the tendon 20 from healing to the bone.
The disclosed methods and products detailed below serve in part to address this and other issues.